fix(compaction): order compaction summary before retained tail (#25851)

packages/opencode/src/session/message-v2.ts

@@ -1104,6 +1104,32 @@ export function filterCompacted(msgs: Iterable<WithParts>) {
       completed.add(msg.info.parentID)
   }
   result.reverse()
+  const compactionIndex = result.findLastIndex(
+    (msg) =>
+      msg.info.role === "user" &&
+      msg.parts.some((item): item is CompactionPart => item.type === "compaction" && item.tail_start_id !== undefined),
+  )
+  const compaction = result[compactionIndex]
+  const part = compaction?.parts.find(
+    (item): item is CompactionPart => item.type === "compaction" && item.tail_start_id !== undefined,
+  )
+  const summaryIndex = compaction
+    ? result.findIndex(
+        (msg, index) =>
+          index > compactionIndex &&
+          msg.info.role === "assistant" &&
+          msg.info.summary &&
+          msg.info.parentID === compaction.info.id,
+      )
+    : -1
+  const tailIndex = part?.tail_start_id ? result.findIndex((msg) => msg.info.id === part.tail_start_id) : -1
+  if (tailIndex >= 0 && tailIndex < compactionIndex && summaryIndex > compactionIndex) {
+    return [
+      ...result.slice(compactionIndex, summaryIndex + 1),
+      ...result.slice(tailIndex, compactionIndex),
+      ...result.slice(summaryIndex + 1),
+    ]
+  }
   return result
 }